A Local Positioning System (LPS) permits an operator to acquire local coordinate measurement and imaging data for an object in the view of the physical hardware of the LPS. For example, an inspector viewing a particular structure on an aircraft may need to know a position on the structure that is defined in the local coordinate system of the aircraft in order to obtain schematics, or other information regarding that structure, that are stored and referenced using the local coordinate system of the aircraft itself.
A Local Positioning System (LPS) may use a pan-tilt unit (PTU) to orient a camera in the direction of an object for which local coordinates are needed. A laser range meter can be used to measure range to the object, or distances can be entered or derived algorithmically. Image data, measured range data, and pan-tilt angles are used along with known calibration points to determine the location of the LPS device relative to the target object. With the relative location known, LPS measurements are converted into the local coordinates of the target object's coordinate system (such as airplane or building coordinates).
An operator may control the PTU, laser range meter, camera devices and other software operations of an LPS using keyboard controls, or interface devices such as joysticks, gamepad controllers, mouse devices, etc. The LPS includes a computer system physically attached to, and collocated with, other components of the LPS. A local operator is generally in close physical proximity to the LPS, for example in the same room as the LPS. This can present difficulties if the operator needs to move around the inspection site to positions that may be out of range of direct contact with the LPS. If an operator, such as an expert inspector, is not physically at the local site, the operator may be require to travel onsite to operate the LPS.
If the LPS computer system supports remote operation, then an operator may be able to use the system from a different physical location. For example Windows Remote Desktop and Citrix on Windows systems, and remote login features of Unix/Linux based systems, can allow remote operators to remotely log into the computer system and operate some aspects of the LPS. However, although these remote login capabilities allow remote users to access the LPS, they generally limit operation of the hardware attached to the computer system and the associated control programs to a single operator at a time. They would not enable simultaneous use of the same LPS by two different users who, for example, might be collaborating on a task. This would create an undesirable scheduling issue wherein if a local user desired to use the LPS, then the remote user would need to exit the LPS control application, and vice versa.
Using remote login capabilities also creates administrative work, as granting remote users access to the LPS computer system requires setup of accounts and administration of passwords. Additionally, using these remote login features require operators to interact with the computer system at the desktop level to gain access to the attached LPS, adding operational complexity for the remote operator. Further, in terms of network bandwidth, replicating desktops on remote computers requires significant network resources, introduces additional latency, and does not always present the best quality of image and video to the remote user.
The use of remote login capability also does not address the issue of a single user connecting to multiple LPS units simultaneously as may occur if two or more LPS units are required to provide full coverage of large object, or an object having occluded regions. If a single operator desired to simultaneously operate two or more LPS units using remote login capabilities, it would be difficult, if not altogether impractical to run multiple remote sessions and control multiple LPS units concurrently, since inputs from the keyboard, mouse, gamepad, or other interface devices are assigned to only one active application at a time, even if the different screens could be presented simultaneously.
Therefore, there is a need to allow use of an LPS by multiple users simultaneously, or simultaneous use of multiple LPS by a single user, or by users not co-located with the physical hardware, while efficiently utilizing network resources.